Creeper installation method and apparatus

ABSTRACT

A method and apparatus for ready replacement of a noncreeper subassembly in a tractor transmission with a creeper subassembly. The method includes subassembly removal and replacement through a window. Removal is by opening the window, reaching in to move, along a subassembly main shaft, a collar which joins the main shaft to a shuttle shaft and in so doing opening a void between the shafts, and then using the void to advantage to manipulate the subassembly out the window. Replacement reverses the same steps. The collar on the creeper subassembly has means for seating a bearing.

FIELD OF THE INVENTION

This invention is related generally to transmissions for tractors andthe like and, more specifically, to methods and apparatus forreplacement of major transmission subassemblies. Still morespecifically, the invention relates to installation of a creeper gearsubassembly in place of a noncreeper subassembly.

BACKGROUND OF THE INVENTION

Transmissions are by their very nature very complex apparatus.Replacement of major transmission subassemblies for as part of repairoperations or for the purpose of achieving different operationalqualities is a difficult and time-consuming task. Major changes in atransmission for the latter purpose are rarely undertaken.

Creepers are helpful in certain very slow operations extending over aprotracted period of time, such as the planting of seedlings. If acreeper is needed, it would usually have been an included option at thetime the tractor is purchased. But tractors usually do not need to beequipped with creeper drives and do not include them.

There are occasions when a farmer who did not anticipate the need for acreeper will need to utilize his tractor for something requiring a veryslow drive speed and wish his tractor had been equipped with a creeper.To make a change in the transmission is at best very difficult,time-consuming and expensive. Rather than undergoing expensivetransmission rebuilding procedures or acquiring a new tractor or, itwould be very desirable to have a simple method for the purpose ofrevising a tractor transmission to include a creeper.

BRIEF SUMMARY OF THE INVENTION

This invention is a simple method and apparatus for replacing anoncreeper subassembly with a creeper subassembly in a tractortransmission. The method of this invention is simple enough that it mayreadily be carried out without substantial disassembly of thetransmission and without the need for major factory-type equipment. Amechanic, such as a mechanic employed by a tractor dealership, canquickly and easily handle the job.

In order to carry out the method of this invention, the transmissionwhich is being modified must include the apparatus of the invention. Themethod and apparatus of this invention will be described together.

The subassembly which must be replaced is in an option section of thetransmission, between the speed section and the range section. Tofacilitate the method of this invention, the transmission case has acovered window at its option section, adjacent to the factory-installednoncreeper subassembly which is to be replaced by a creeper subassembly.

The replaced subassembly and the replacing subassembly each have thesame axial dimension, and each have a first end and an opposite secondend. Each of these subassemblies is joinable at its first end by a mainshaft to a transmission shuttle shaft which is in the range section ofthe transmission by splined engagement of the distal ends of suchshuttle shaft and main shaft in the opposite ends of a collar which isin an internal orifice in the transmission case. More specifically, abearing cone which is supported on the outside of the collar is seatedin a bearing cup on the transmission case orifice.

As will appear, the apparatus of this invention relates to, among otherthings, the relationship of the distal ends of the main shaft andshuttle shaft, the relationship of the collar to the main shaft, and thenature of the collar on the main shaft of the creeper subassembly.

The sequential steps of the method of this invention are as follows:

To gain access to the inside of the option section of the transmission,the transmission window is opened by removing the cover. This may bereadily carried out by removing whatever fastening means was used toseal the cover over the window.

To facilitate the method of this invention, the collars on the splineddistal ends of the main shafts of the the factory-installed noncreepersubassembly and the creeper subassembly are held at the right positionson such splined distal ends by stop means on the main shafts. Such stopmeans are movable along their respective main shafts after they havebeen released from their positions on the main shafts. Snap rings areheld in place by butt means on their main shaft and their own springpressure.

In order to begin the removal of the noncreeper subassembly, a mechanicreaches through the window, releases the stop means, and moves it alongthe main shaft in a direction away from the shuttle shaft, that is, intofurther insertion along the main shaft. When the stop means is a snapring, it may be readily spread by reaching through the window and usinga common snap-ring spreading tool.

By moving the snap ring along the main shaft in a direction away fromthe shuttle shaft, the collar is made free to do so as well. This ismade possible because the end of the noncreeper main shaft is splined asufficient distance from its distal end to accommodate such collarmovement.

Just as important is the positioning and dimensioning of the main shaftwith respect to the shuttle shaft. The distal ends of the main shaft andthe shuttle shaft are spaced apart when fully installed such that themovement of collar further onto the main shaft and away from the shuttleshaft, as described above, creates a void between such distal ends.

The noncreeper subassembly may then be moved into the void, toward theshuttle shaft. This allows the opposite or second end of the subassemblyto become unseated. This in turn allows a mechanic to manipulate thenoncreeper subassembly in various directions and into variousorientations to remove it from the transmission through the window. Thedimensions of the window are sufficient for this purpose.

When the factory-installed noncreeper subassembly has been removed, thereplacement creeper subassembly is inserted through the window into thetransmission case and manipulated into position in generally the reversemanner, taking full advantage of the void space previously mentioned.

This is done by first moving the first end of the creeper subassembly,more specifically, its main shaft distal end, into the void and towardthe shuttle shaft as much as possible, so that the opposite or secondend of the creeper subassembly can be brought into proper alignment withthe position where it is to be seated. This is possible because thecreeper subassembly has a main shaft similar to the main shaft of thenoncreeper subassembly, accommodating movement of a collar (sometimesreferred to as the creeper collar) therealong near its distal end; andwhen the creeper subassembly is first inserted the creeper collar is infull engagement with the creeper main shaft.

After the second end of the creeper subassembly is seated, the creepercollar is moved toward the shuttle shaft and engaged with it ingenerally the same manner in which the noncreeper collar was engagedwith it. When the creeper collar is in the right position, a snap ringor other stop means on the creeper main shaft is moved into a positicnnear the distal end of the main shaft to prevent the creeper collar fromsliding further onto the main shaft. This snap ring is like the snapring previously described and the creeper shaft has butt means to holdthe snap ring in place.

The creeper collar, which supports a bearing cone, has anaxially-adjustable means on it for securing the bearing cone in seatedposition against the bearing cup. In a preferred form, the creepercollar has a threaded portion adjacent to the bearing cone thereon and alock washer and lock nut are on the threaded portion to move the bearingcone into its proper seating with the bearing cup.

The lock washer is keyed on its inner diameter to the creeper collar, bymeans of a slot therein, and, when the bearing has been properly seatedby turning the nut along the threaded portion of the creeper collar, akeying means on the outer diameter of the lock washer is bent intoengagement with a slot on the lock nut. In this manner, accidentalremoval or loosening of the structure is avoided.

After the creeper subassembly is fully in place and engaged aspreviously described, a lay-shaft assembly and shift apparatus, whichare secured to the inside surface of a window cover, are inserted intothe transmission case and engaged in their proper position. Then, thewindow is closed by securing such window cover to the transmission caseby the use of bolts or other fastening devices.

The method steps of this invention may be carried out quickly and easilyand do not require unusual tools or equipment.

The apparatus of this invention, as already described, includes awindowed transmission, a dimensioning of the main shaft such that a voidspace is defined between the distal ends of the shuttle shaft and mainshaft, a splined section of sufficient axial dimension near the distalend of the main shaft such that the collar may be fully received ontothe distal end to create the aforementioned void space, and the creepercollar characteristics previously described.

OBJECTS OF THE INVENTION

It is the principal object of this invention to provide an easy methodfor replacement of one major gear subassembly with another gearsubassembly.

Another object of this invention is to provide a method for easyreplacement of a noncreeper gear assembly with a creeper gear assembly.

Another object of this invention is to provide an improved method andapparatus for making major revisions in a tractor transmission toinclude a creeper drive.

These and other objects of the invention will be apparent from thefollowing additional descriptions and from the drawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary schematic side elevation of a transmissionsection showing a factory-installed creeper subassembly.

FIG. 2 is a similar side elevation showing a factory-installednoncreeper subassembly to be replaced using the method of thisinvention.

FIGS. 3-5 are sir:ilar side elevations illustrating sequential steps inthe removal of the noncreeper subassembly shown in FIG. 2.

FIGS. 6-8 are similar side elevations illustrating sequential steps inplacement and installation of a creeper subassembly.

FIG. 9 is an enlarged fragmentary schematic view, taken from a differentangle, showing the fully-installed replacement creeper subassembly,including a lay-shaft assembly, a shift apparatus, and a transmissioncover.

DETAILED DESCRIPTIONS OF PREFERRED EMBODIMENTS

The figures illustrate a portion of a transmission 10 of a tractor orother similar device. Each of the figures shows a fragmentary portion ofthe speed section 12 of transmission 10, a fragmentary portion of therange section of transmission 10, and the option section 16 oftransmission 10 which is between speed and range sections 12 and 14.

Speed section 12 includes an input shaft 18 and a drop shaft (not shown)to drive a gear 19 engaged with a transfer gear 20. Transfer gear 20 ison the subassembly which is the principal subassembly of concern in thisinvention.

As illustrated in FIGS. 1-8, range section 12 has a shuttle shaft 21which is axially-aligned with the main shaft (described later) of thegear subassembly in option section 16 and is joined to it by means of acollar (described later).

Transmission 10 has a case 22 with a window 24, the position of which isillustrated by phantom lines in FIGS. 1-8. Window 24 is adjacent to thegear subassembly in option section 16 and is dimensioned to allowremoval and insertion of such gear subassembly. More specifically, it isdimensioned to allow removal of a noncreeper subassembly 26 shown inFIGS. 2-5 and to replace it with a creeper subassembly 28 shown in FIGS.6-9.

FIG. 1 illustrates a factory-installed creeper subassembly 30 which hasno relationship to this invention. Creeper subassembly 30 is slightlydifferent from the creeper subassembly 28 which is designed to replacenoncreeper subassembly 26. And, the noncreeper subassembly 26 which maybe replaced is designed to accommodate the replacement operations. Suchdifferences will be made apparent by the description which follows.

FIGS. 2-9 serve to illustrate the sequence of steps followed to replacefactory-installed noncreeper subassembly 26 with creeper subassembly 28.Such replacement operation may be carried out simply and with minimaltools. It is intended that such creeper installation be carried out awayfrom the factory by a dealer.

Window 24 of transmission case 22 has a cover which is bolted onto thetranmission case. The first step in installing the creeper subassemblyis to remove the window cover. At that point, factory-installednoncreeper subassembly 26 will be in the condition and positionrepresented by FIG. 2.

A snap ring 32 on noncreeper main shaft 34 is fixed in place on suchshaft by butt means 36. Butt means by itself does not interfere withmovement of the collar. Snap ring 32 serves to hold noncreeper collar 38in position on main shaft 34 such that the opposite ends of collar 38are splined onto the opposed distal ends 40 and 42 of main shaft 34 andshuttle shaft 21, respectively. Supported on noncreeper collar 38 is abearing cone 44 which is engaged with a bearing cup 46. Bearing cup 46is affixed to an internal orifice 48 in transmission case 22.

The next step in installation of creeper subassembly 28 in place offactory-installed noncreeper subassembly 26 is to reach through window24 and grasp snap ring 32 to spread it and thus release it from itsengagement with main shaft 34. This may be done using a standardsnap-ring spreading tool. While snap ring 32 is spread, it is movedalong main shaft 34 in a direction away from shuttle shaft 21, to theposition shown in FIG. 3.

Main shaft 34 has a reduced diameter end portion 50 which is splined aconsiderable distance from the end of the shaft. This allows noncreepercollar 38, now that snap ring 32 has been moved away, to be moved alongmain shaft 34 until it and snap ring 32 (which is pushed by it) engageshoulder 52. This sliding of noncreeper collar 38 opens up the void 54which exists between distal ends 40 and 42 of main shaft 34 and shuttleshaft 21, as illustrated in FIG. 4. The lengths of main shaft 34 andshuttle shaft 21 are limited to allow creation of such void.

The next step is to use void 54 to move factory-installed noncreepersubassembly 26 in an axial direction toward shuttle shaft 21, thusdisengaging the opposite or second end of subassembly 26 from its seat58. This is illustrated in FIG. 5.

Thus unseated, noncreeper subassembly 26 may be tilted and manipulatedthrough window 24 to remove it from transmission case 22. Second end 56of noncreeper subassembly 26 may be the first portion of the subassemblycoming out of window 24.

In a reverse manner, creeper subassembly 28 will be manipulated throughwindow 24, distal end 60 normally being the first portion of thesubassembly to pass through window 24. After creeper subassembly 28 isinside transmission case 22, it is brought into axial alignment withshuttle shaft 21, to the position shown in FIG. 6. This alignment ismade possible by the presence of void 54, previously described. At thispoint, creeper collar 62 is fully inserted over distal end 60 such thatvoid 54 may be utilized in the manner described.

The next step is to seat creeper end 64 onto seat 58 by movingsubassembly 28 to the right, as shown in FIG. 7. Then, creeper collar 62is moved by sliding it along creeper main shaft 66 through void 54 andinto splined engagement with shuttle shaft 21. Creeper main shaft 66,like noncreeper main shaft 34, is splined a sufficient distance alongits length from its distal end to accommodate such positioning andmovement.

When creeper collar 62 is positioned in proper engagement with shuttleshaft 21 and main shaft 66, creeper snap ring 67 is moved from theposition shown in FIG. 6 to its final position as shown in FIG. 7. Snapring 67 is held in that position by butt means 65 on main shaft 66. Theresult of these operations is illustrated in FIG. 7.

Before describing the remaining replacement operations, a description ofcreeper collar 62 and the apparatus secured thereto will be helpful.Creeper collar 62 supports a bearing cone 68 (similar to bearing cone44) and has a nut-engaging threaded portion 70 adjacent to bearing cone68 and extending to the end of the collar into which main shaft 66 isinserted. A lock washer 72 is placed on threaded portion 70 and is heldthereon by a lock nut 74. Lock washer 72 is keyed at its inner diameterto the outside of creeper collar 62 by a common key and slot arrangement(not shown). Lock washer 72 also has a keying means 76 at its outerdiameter positioned to be bent into engagement with a slot in the outerdiameter of lock nut 74.

Lock nut 74 and lock washer 72 on threaded portion 70 are used in thenext step in the method. Lock nut 74 is tightened to seat bearing cone68 properly against bearing cup 46. When the proper seating is achieved,keying means 76 on lock washer 72 is bent to the position shown in FIG.8 to engage lock nut 74, thus holding the bearing in proper position.

To assure that the bearing is in proper position and condition for use,lock nut 74 may be backed off just a bit, perhaps one quarter of a turn,prior to setting it in place by placement of keying means 76. A blow tothe bearing cone 44 through exposed creeper collar 62 or lock nut 74 maybe used to condition the bearing for use.

The next step is installation of a lay-shaft assembly 78 and shiftapparatus 80, shown in FIG. 9. Lay-shaft assemlly and shift apparatus 80are supported by a window cover 82. When lay-shaft assembly 78 and shiftapparatus 80 are in place, window cover 82 is secured to transmissioncase 22, such as by bolting, thus closing window 24.

The parts of this inventive apparatus may be made using materials andmethods well known to those skilled in the art.

While the principles of this invention have been described in connectionwith specific embodiments, it should be understood clearly that thesedescriptions are made only by way of example and are not intended tolimit the scope of the invention.

What is claimed:
 1. A method for replacing a noncreeper subassembly witha creeper subassembly in a transmission with a window adjacent to thenoncreeper subassembly, each such subassembly having a first end and anopposite second end and being joined at its first end by its main shaftto a transmission shuttle shaft by splining of opposed distal ends ofsuch shafts, which are axially spaced to form a void therebetween, inopposite ends of a collar journaled in a bearing cup on a transmissioncase orifice, each subassembly having stop means on its main shaftlimiting shaft insertion in the collar, comprising:opening the window:reaching through the window and unseating the noncreeper collar from thebearing cup such that said collar no longer joins the main shaft to theshuttle shaft; moving the noncreeper subassembly in the void toward theshuttle shaft to unseat the noncreeper second end, and from thatposition manipulating the noncreeper subassembly out of the case throughthe window; inserting a creeper subassembly through the window and intothe case, said creeper main shaft having a creeper collar thereon andmeans to secure the creeper collar in position; aligning the creepersubassembly; securing the creeper collar into engagement with theshuttle shaft by positioning of said stop means; and closing the windowby securing to the case a window cover which supports a layshaftassembly and shift apparatus for engagement with the creepersubassembly.
 2. The method of claim 1 wherein the unseating and removingsteps comprise:moving the stop means on the noncreeper main shaft awayfrom the distal end thereof; and sliding the noncreeper collar furtheronto the noncreeper main shaft to remove it from the shuttle shaft andopen the void between the distal ends.
 3. The method of claim 2 whereinthe noncreeper stop means is a snap ring held in fixed axial positionagainst a butt means on the noncreeper main shaft, and wherein themoving step comprises spreading the snap ring to disengage it from thebutt means and sliding it along the noncreeper main shaft in a directionaway from the shuttle shaft.
 4. The method of claim 2 wherein thecreeper collar has a bearing cone supported thereon and anaxially-adjustable means thereon adjacent to the cone and wherein thealigning and securing steps comprise:inserting the distal end of thecreeper main shaft into the void and, with it located in that position,axially aligning the creeper main shaft with the shuttle shaft; seatingthe end of the creeper subassembly by moving the creeper main shaftaxially away from the shuttle shaft; sliding the creeper collar alongthe creeper main shaft, through the void and into engagement with theshuttle shaft; moving the creeper stop means toward the distal end ofthe creeper main shaft into a position holding the creeper collar in itsengagement with the shuttle shaft; and moving the axially-adjustablemeans along the creeper collar to seat the bearing cone on the bearingcup and then locking the axially-adjustable means in position on thecreeper collar.
 5. The method of claim 4 wherein the creeper collar hasa nut-engaging threaded portion adjacent to the cone and wherein theaxially-adjustable means comprises a lock nut and lock washer on thethreaded portion, said lock washer being keyed to the creeper collar andhaving means to key it to the nut, and wherein the locking stepcomprises keying the lock washer to the lock nut.
 6. The method of claim4 wherein each of the stop means is a snap ring engageable on itsrespective main shaft in fixed axial position against a butt means andthe moving steps comprise spreading the snap ring and sliding it alongits main shaft.